Updated the test system

test/words.test.js

@@ -0,0 +1,45 @@
+const expect = require('expect');
+const {words} = require('./_30s.js');
+
+test('words is a Function', () => {
+  expect(words).toBeInstanceOf(Function);
+});
+test("words('I love javaScript!!') returns [I, love, javaScript]", () => {
+  expect(words('I love javaScript!!')).toEqual(['I', 'love', 'javaScript']);
+});
+test("words('python, javaScript & coffee') returns [python, javaScript, coffee]", () => {
+  expect(words('python, javaScript & coffee')).toEqual(['python', 'javaScript', 'coffee']);
+});
+test('words(I love javaScript!!) returns an array', () => {
+  expect(Array.isArray(words('I love javaScript!!'))).toBeTruthy();
+});
+test('words() throws an error', () => {
+  expect(() => {
+    words();
+  }).toThrow();
+});
+test('words(null) throws an error', () => {
+  expect(() => {
+    words(null);
+  }).toThrow();
+});
+test('words(undefined) throws an error', () => {
+  expect(() => {
+    words(undefined);
+  }).toThrow();
+});
+test('words({}) throws an error', () => {
+  expect(() => {
+    words({});
+  }).toThrow();
+});
+test('words([]) throws an error', () => {
+  expect(() => {
+    words([]);
+  }).toThrow();
+});
+test('words(1234) throws an error', () => {
+  expect(() => {
+    words(1234);
+  }).toThrow();
+});